Fig. 5

CDKN2A deletion by FISH stratifies survival for grade 4 tumors, but not lower grades. K-M survival curves for tumors above and below 30% homozygous CDKN2A deletion at each histologic grade are shown for primary tumors (a) and first recurrence tumors (b). In primary tumors, only 2 of 86 grade 2/3 tumors showed ≥ 30% CDKN2A homozygous deletion, and both patients were still living at the time of analysis. 6 of 22 primary grade 4 tumors showed ≥ 30% deletion, and patients with these tumors had significantly shorter survival than grade 4 tumors without loss. Among recurrences, no grade 2 tumors showed ≥ 30% deletion. Recurrent grade 3 tumors with and without CDKN2A deletion showed similar survival times. As with primary tumors, grade 4 recurrences with CDKN2A deletion showed significantly decreased survival compared to those grade 4 tumors without deletion. Survival curves for tumors that would hypothetically be upgraded at lower CDKN2A homozygous deletion cutoffs of 10% (c) or 20% (5D) are shown in relation to histologic grade 4 tumors. Although more tumors are identified as having CDKN2A deletion at these cutoff values, meaningful improvements in prognostic stratification are not seen